<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <div class="houdunren" data="hd">houdunren.com</div>
        <div class="houdunwang">houdunwang.com</div>
        <div class="xiangjun"><!-- 向军大叔 --></div>
      </div>
    <script>
 
const app = document.querySelector(`#app`)
  console.log(app.children) //所有子元素
    </script>
</body>
</html>